1. Field of the Invention
This invention relates to a low noise level automotive internal combustion engine, and more particularly to a cylinder block configuration provided with a beam member for reinforcing main bearing caps to decrease engine noise.
2. Description of the Prior Art
In conventional automotive internal combustion engines, a crankshaft is rotatably supported through main bearing shells by a plurality of main bearing carring sections and bearing caps which are respectively secured to the bearing carrying sections. With this configuration in which each main bearing cap is formed independently, each main bearing cap tends to be vibrated forward and rearward or in the downward direction, by vibrational force applied from the crankshaft due to combustion impact force. This brings about the vibration of the cylinder block skirt section, which causes noise to emit outside of the engine. Such phenomena are particularly prominent in the case of cylinder blocks made of a light alloy.